Haha, Kevin, I initially thought about that HUGE cap when I initially was looking at Adam's post over at Bottlehead. That is one big mother!

I also saw this crazy tube amp build over at DIYAudio where the builder daisy-chained hundreds of vintage oilers, the thing must have weighed several hundred pounds. It's buried in the gallery somewhere.

The big caps (the silver ones that are upside down on top, and the blue ones in back) were dirt cheap. $10 each (see the links at the bottom of my first post in that thread). The ClarityCap ESA 100uf were expensive. I forget exactly, but I think they were about $85 each, maybe more.

OK...price is not a barrier then. Is the improvement of all those big round thingies (kidding) equal to the improvement when speedball was first added? (I am very much a form follows function type of a guy....) Thought I will say I have not a clue how they are connected.

I don't think I can realistically quantify the change caused by one vs. the other. As I understand it, the Speedball helps ensure that the tubes are consistently operating at their optimum operating point, while the caps help to improve transient bass response in terms of speed and impact. Which one is more important? Dunno. I'd bet on the Speedball. But the caps in the power supply cost a whopping $30-40 to replace, and the supply of those big blue Icar caps is limited. I would jump on those while they are still available, then buy the Speedball when funds allow.

To be clear: other than the ClarityCap coupling caps mounted underneath, the caps I bought were all about $10/each. If you just used three of the Icars in the power supply, it would cost you $30. I used two of the 100uf Temco oilers on top instead of a third 200uf Icar, so I spent about $40 replacing the caps in the power supply. That's why I said $30-40. The Temco caps are readily available new and not limited in supply. I was referring to the Icars beig limited in supply.

I would, if (a) this weren't perfectly functional as-is (which makes it difficult to get motivated to rip it out), (b) I didn't have a backlog of 5-6 other amps I want to build or am in the process of building, (c) a larger case would fit into my headphone amp rack, which is already overflowing with amps, DACs and headphones as-is. But in its current position, the Crack is wedged in next to my DAC, with not a millimeter to spare. At some point, I will just give this one away, and build a new one.

To be clear: other than the ClarityCap coupling caps mounted underneath, the caps I bought were all about $10/each. If you just used three of the Icars in the power supply, it would cost you $30. I used two of the 100uf Temco oilers on top instead of a third 200uf Icar, so I spent about $40 replacing the caps in the power supply. That's why I said $30-40. The Temco caps are readily available new and not limited in supply. I was referring to the Icars beig limited in supply.

May I ask where you found the coupling caps for $10 and the icar caps for that cheap as well?

The ClarityCap ESA 100uf 250V were $85 each from Madisound. I don't know if they still carry them, but they are closing out their stock of ClarityCap SA 630V caps. 100uf caps are only $40 each while stocks last.

As for the Icar caps, check out the links at the bottom of the Bottlehead post linked to in the first post in this thread.